1. Technical Field
The present invention relates to a permanent magnet type motor in which a permanent magnet is incorporated into a rotor core, and a method for manufacturing the permanent magnet type motor.
2. Description of the Related Arts
Motors using a permanent magnet are broadly classified into a surface permanent magnet type (SPM motor) in which the permanent magnet is disposed on a surface of a shaft, and an interior permanent magnet type motor (IPM motor) in which the permanent magnet is incorporated into a rotor core.
Rotor shapes of the IPM motor are very diverse, and a method for manufacturing the rotor is adopted depending on the respective shapes and intended purposes of the motor. Generally, a manufacturing method has been adopted in which after the rotor core is shrinkage fitted to the shaft, an adhesive is applied to both sides of a magnet insertion hole and the permanent magnet, and the permanent magnet is inserted into the magnet insertion hole from both end surfaces of the rotor core to harden the adhesive.
Since the magnet insertion hole is opened in the both end surfaces of the rotor core, the adhesive having high-viscosity to an extent that does not droop out of the magnet insertion hole is used.
As a technique concerning the incorporation of the permanent magnet, a method for manufacturing the motor is disclosed in which permanent magnet embedding holes penetrating in an axial direction are provided at a plurality of locations in the rotor core, the permanent magnet is directly coated using the adhesive, and then the permanent magnet and the rotor core are also bonded to each other (for example, see Japanese Patent Application Laid-Open Publication No. 2003-199303).